This invention relates to the shaping of bonded abrasive products, particularly abrasive compacts.
Abrasive compacts are well known in the art and are used extensively in industry for the abrading of various workpieces. They consist essentially of a mass of abrasive particles generally present in an amount of at least 70 percent, preferably 80 to 90 percent, by volume of the compact bonded into a hard conglomerate. Compacts are polycrystalline masses having diamond-to-diamond bonding and can replace single large crystals. The abrasive paricles of compacts are invariably ultra-hard abrasives such as diamond and cubic boron nitride. Diamond compacts are also known in the art as polycrystalline diamond or pcd.
Abrasive compacts are often bonded to a substrate such as a cemented carbide substrate. Such products are known in the art as composite abrasive compacts. Examples of specifications which describe composite abrasive compacts are U.S. Pat. Nos. 3,745,623 and 3,743,489 and British Specification No. 1,489,130.
It is possible to produce large disc-shaped diamond composite compacts. The carbide substrate of such large composite compacts tends to bend to a bow-shape during manufacture. Industry calls for diamond compact layers of such composite compacts within precise tolerances. To meet this requirement in the light of the bending problem, it is the practice to produce composite compacts with thicker diamond layers which are then lapped to the required thickness. Lapping is achieved using diamond and much diamond is consumed during lapping. This is expensive.